import math
x1, y1, x2, y2 = map(float, input().split())

r = (x1 - x2) ** 2 + (y1 - y2)**2
r = math.sqrt(r)
print(format(r, '.8f')) import math math x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 r = (x1 - x2) ** 2 + (y1 - y2)**2 r (x1 - x2) ** 2 + (y1 - y2)**2 (x1 - x2) ** 2 x1 - x2 x1 x2 2 (y1 - y2)**2 y1 - y2 y1 y2 2 r = math.sqrt(r) r math.sqrt(r) math.sqrt math sqrt r print(format(r, '.8f')) print format(r, '.8f') format r '.8f' x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 r = math.sqrt(r) math.sqrt(r) r x2, y2 = map(float, input().split()) map(float, input().split()) x2 y2 = map(float, input().split()) map(float, input().split()) y2 y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 r = (x1 - x2) ** 2 + (y1 - y2)**2 (x1 - x2) ** 2 + (y1 - y2)**2 r
import math
x1, y1, x2, y2 = map(float, input().split())

r = (x1 - x2) ** 2 + (y1 - y2)**2
r = math.sqrt(r)
print(format(r, '.8f'))
